'Icebusters': 30 Years Since the Maiden Voyage of Shuttle Discovery (Part 2)

Thirty years ago, this week, the Shuttle Discovery—which would become, in time, the most-flown member of NASA’s fleet of orbiters—embarked on her maiden space voyage, launching from Pad 39A at the Kennedy Space Center (KSC) on 30 August 1984. Aboard Discovery were Commander Hank Hartsfield, Pilot Mike Coats, Mission Specialists Mike Mullane, Steve Hawley, and Judy Resnik, and Payload Specialist Charlie Walker. During their six days in space, they became the first shuttle crew to deploy as many as three commercial satellites, they extended an experimental solar array “wing,” and they became forever known to history as “The Icebusters.” However, as described in yesterday’s AmericaSpace history article, the 41D mission had already experienced more than its fair share of excitement, before Discovery even departed the launch pad.

Less than eight hours after launch, at 4:40 p.m. EDT, the first communications satellite, SBS-4 for Satellite Business Systems, was sent spinning out of Discovery’s payload bay; the wrist camera on the Remote Manipulator System (RMS) mechanical arm captured the successful 87-second firing of its Payload Assist Module (PAM)-D booster. Early on Day Two, however, a quite different satellite—the U.S. Navy’s Syncom 4-2—was deployed, in a quite different way. Instead of sitting “vertically” in the payload bay, it lay horizontally, and was spring-ejected in a manner not dissimilar to a frisbee. Since NASA’s fee to its customers was proportional to how much length a satellite occupied in the payload bay, the Syncoms were deliberately designed as full-width, stubby drums. This enabled them to precisely fit the width of the bay and minimized their length. In shape, they took the form of 3,100-pound (1,400-kg) cylinders and were designed to provide worldwide, high-priority communications between ships, aircraft, submarines, and land-based stations for the U.S. armed forces, as well as the Presidential Command Network. Syncom was also known by another name—“Leasat”—because its services were “leased” by the U.S. Navy from prime contractor Hughes.

Syncom 4-1, the first of new series, was assigned to 41D, originally scheduled for June 1984, whilst Syncom 4-2 was due to launch aboard Mission 41F in August. By the time of 41D’s on-pad abort, the 41F payload—which also included SBS-4 and Telstar-3C—was in the final stages of processing for its early August launch. In the wake of the abort, NASA considered it more straightforward to switch the entire 41F commercial payload onto 41D, and reschedule Syncom 4-1 for launch later in the year. Consequently, the second Syncom 4 entered orbit ahead of the first. The Syncom 4-2 deployment came at 9:16 a.m. EDT on 31 August and occurred perfectly; the satellite departed the bay at a velocity of 2.3 feet per second (0.7 meters per second), spinning at a couple of revolutions per minute. Very soon, it was in the process of executing the required maneuvers to insert itself into geostationary transfer orbit.

What did not work quite so well was the IMAX motion-picture camera, which had previously flown on shuttle mission 41C and would fly again on 41G and whose footage subsequently formed the basis of the 1985 movie “The Dream is Alive.” Operation of this large and unwieldy camera was Mike Coats’ responsibility, and one of its earliest uses was to film the deployment of Syncom 4-2. Unfortunately, during this time, in the words of the official NASA mission report, it “jammed.” The background to what caused this jam has been explained with some color by Mike Mullane and Steve Hawley. As Syncom left the bay, Hank Hartsfield was filming the deployment when, all of a sudden, its belt-driven magazine sucked up a shank of Resnik’s black hair, which weightlessness had liberated into flowing tresses. The IMAX ground to a stop, blowing the circuit breaker in the process. Eventually, with scissors, they freed Resnik’s hair and Coats took the camera down to the middeck to repair it. When the time came for Hartsfield to report the incident to Mission Control, Resnik gave him a threatening stare and he respected her embarrassment, telling the ground simply that IMAX had jammed and Coats was working to fix it.

IMAX did have a belt guard but, as Hawley told the NASA oral historian, “for whatever reason we decided we didn’t need to fly it. I don’t know if we were trying to save weight, but we decided we didn’t need this belt guard.” Coats worked for several hours, methodically removing shreds of Resnik’s hair from the camera, and for a time it seemed unlikely that IMAX would work. At length, he restored it to operation and it was used for a variety of tasks, including the deployment of the experimental OAST-1 solar array, provided by NASA’s Office of Aeronautics and Space Technology. It was an amazing machine. “The thing pulled so much film, so fast,” recalled Hawley, “and it’s [so] big that, in zero-G, it will actually torque you like a gyroscope! To use it, you really have to be affixed to something, because it will rotate you!”

Following the Syncom 4-2 deployment, the third and final satellite, Telstar-3C, was sent spinning out of the payload bay at 9:25 a.m. EDT on 1 September. Like SBS-4 and most previous PAM-D payloads, it was a cylindrical, spin-stabilized satellite, coated with solar cells for electrical power. For Steve Hawley, it was also particularly memorable, because its purpose-built ground station lay at a place called Hawley in eastern Pennsylvania. In his oral history, he admitted that he had previously never heard of the place, “but it’s spelled the same way. After the flight, I got to go to Hawley, Penn.!”

With three satellites successfully deployed and on their way to geostationary orbit, the final days of 41D were to be spent on their other payloads, most notably OAST-1, which was primarily Judy Resnik’s responsibility. Its hardware sat atop a Mission Peculiar Experiment Support Structure (MPESS) and consisted of a number of experiments. Of these, the most notable was the solar array, which, when unfurled, projected 103 feet (31.5 meters) “above” Discovery’s payload bay—taller than a 10-story building. Although it was not designed to generate electricity, the intent was to demonstrate the structural dynamics of a large array, placing it under different levels of stress, including thruster firings, to understand its behavior. The primary structure was Kapton and the array comprised 84 panels, which folded out, accordion-like, on an epoxy-fibreglass mast from a 5-foot-high (1.5-meter) canister on the MPESS.

Hank Hartsfield works with the IMAX camera on Discovery’s middeck. Photo Credit: NASA

After full deployment, the array had a triangular cross-section, longitudinally stabilized by short guide wires between interconnecting battens. On Day Three, soon after the Telstar deployment, Resnik began the first part of the experiment, extending the array to 70 percent open. To do this, a “nut” with internal threads rotated at the top of the storage canister, causing the rollers to move up through the threads and allowing the longerons to straighten and the guide wires to keep the structure rigid. The initial phase of mast extension unlatched the containment box lid, gradually unfolding the solar array blankets. In the first test, when the array reached the 70-percent-open position, a tension bar was deployed to pull the unfurled section “flat.” It was at this stage that the first series of structural dynamics tests were conducted, and the following day, 2 September, the array was extended to its full height.

“Surprisingly,” recalled Hank Hartsfield, “once the thing is deployed, it’s fairly rigid. In fact, one of the big experiments we did was to turn off the control systems on the orbiter and let it get really stable and then fire the thrusters and … measure how the array oscillated.” The array turned out to be much “stiffer” than engineers had anticipated, and by the time Hartsfield and Coats prepared for the second set of thruster firings, which were intended to increase the motions, the array had almost stopped moving completely. On a couple of occasions, Steve Hawley was given the chance to perform the firings. “Some of it required inputting jet firings simultaneously in different directions,” he told the oral historian, “so that was where I got to play. Mike Coats was primarily responsible for making the input, but some of the times when we had to make a yaw and a pitch or roll simultaneously, it’s easier for two guys to do that.”

The array had only a few transducer cells for test purposes, but, had it been operational, a structure of its size would have been capable of generating up to 12 kilowatts of electrical power. For the 41D crew, the size of the array was one of its most impressive features. “At sunrise or sunset,” remembered Hawley, “the first thing that either the last bit of sunlight or the first bit of sunlight would hit was the solar array and it would make it almost look like it was lighting up with its own source of internal illumination. Everything else would be dark and the solar array would be glowing gold.”

Also spectacular, although for different reasons, was another “structure” which extended not from Discovery’s payload bay … but from a nozzle normally use to dump the crew’s urine overboard. Early on 1 September, unusual temperature data from one of these dumps suggested that a large icicle had formed around the nozzle on the exterior of the vehicle. “Heaters on the exit nozzle are supposed to ensure the fluid separates cleanly,” Mike Mullane wrote in his 2006 memoir, Riding Rockets, “and does not freeze to it.” Mission Control suspected that an icicle might have formed, but since the exit point of the waste nozzle was located on the port side of the middeck, it was impossible to view it with anything other than the camera on the RMS.

Hank Hartsfield duly used the arm to take a look and, lo and behold, there was an icicle, measuring three-quarters of a metre in length and about 12 inches (30 cm) wide. If left to its own devices, the icicle might break off during re-entry, potentially damaging the critical thermal protection system. Ice from dump nozzles had caused damage to Mission 41B during re-entry. Initial attempts to dislodge it focused on using the Reaction Control System (RCS) thrusters were unsuccessful. On the 2nd, Discovery’s cabin pressure was reduced, preparatory to a contingency EVA by Mullane and Hawley the following day. Mullane was thrilled, but Hawley was cautious; the location of the icicle—just aft of the middeck entry hatch—was virtually inaccessible to a spacewalker.

Still, the EVA remained an option and as the crew prepared for bed that evening, they reckoned that it was the only solution. Just before bedding down, fellow astronaut Jerry Ross, the Capcom in Mission Control, told them of a sudden change. There would be no EVA, but they would be asked to dislodge the icicle with the tip of the RMS. Although Hartsfield was not the primary operator of the mechanical arm, he insisted on doing the job. If anyone dinged a brand-new orbiter on its maiden voyage, it had to be the commander’s responsibility. Fellow astronaut Sally Ride had worked a procedure in the simulator and she read the instructions up to them. Hawley felt that it was a good plan. Mullane, on the other hand, was upset to have lost his chance to do a spacewalk.

The icicle drifts away from Discovery, after being successfully detached by the RMS. Photo Credit: NASA

Yet the option of knocking the icicle free with the RMS was itself fraught with difficulty … and danger. “One of the rules in those days,” said Hawley, “was you’re not allowed to operate the arm in a place where you can’t see what it’s doing. I was supposed to go down to the side hatch window and watch as best I could, while Henry drove the arm to knock the ice off. He would move it through a pre-determined trajectory and, if he did it properly, they knew from the ground simulations that it would hit the ice.”

Hartsfield’s jab at the ice was successful and, within minutes, Mullane was able to photograph the spear-like icicle drifting away. With “Ghostbusters” having arrived in cinemas in June 1984, the 41D crew earned themselves a new moniker: Icebusters. Although the icicle was gone, its presence had caused another problem. “We were told we could not use the urinal for the rest of the mission,” Mullane wrote, “for fear another ice ball could jeopardize us.” They would still be able to use the shuttle’s toilet for “solid wastes,” but were forced to use “Apollo-style” plastic bags for liquids; Mission Control told them that there was sufficient remaining volume in the waste water tank for about three man-days’ worth of urine, meaning that Resnik could use it, if needed. However, she was keen to hold onto her feminist sensitivities, it seems, and elected to use the plastic bags. At length, the pragmatic gentleman in Hank Hartsfield came to the fore: “Judy … had a hard time with the bag,” he told the oral historian. “I said, ‘I don’t care what the ground says. You use the bathroom. The rest of us will do the bag trick.’”

Another problem quickly arose. In microgravity, fluids do not readily remain at the bottom of bags, but begin floating around, and it became clear that the astronauts would need to put something in place to soak up the urine. They stuffed dirty towels, underwear and socks into the urine bags to act as an impromptu absorbent. As the bags gradually filled up the waste tanks under the middeck floor, the unsanitary environment was distinctly unpleasant. Randy Stone, the flight director at the Johnson Space Center (JSC) in Houston, Texas, asked his superiors for permission to tell the crew to reconfigure one of their water tanks into a waste tank. “It was easy to do,” Hartsfield recalled, “just a quick plumbing thing … but there was a big concern about turning the orbiter around. They had the idea that if they converted a water tank to a waste tank, it would add another week to the [processing] flow at the Cape to get [Discovery] ready to go again.” Stone’s request to senior management was rejected, twice. Years later, Hartsfield would wonder whether he ought to have requested a private medical conference and enforced a decision. After the flight, he spoke to several engineers and managers, who offered their apologies; ironically, replumbing a water tank into a waste tank would not have affected Discovery’s processing schedule at all.

Offering two quite different perspectives of Discovery’s return to Earth on 5 September were Charlie Walker, seated in the darkened middeck, and Steve Hawley, riding in the flight engineer’s seat and facing into the forward flight deck windows. “There’s a bright kind of plasma plume that seems to form above the orbiter during re-entry,” Hawley recalled, “and it comes in through the overhead windows. You get this soft kind of pink, whitish, orangish glow that develops and encircles the orbiter.” Mike Mullane remembered seeing ribbon-like vortices of white-hot plasma streaming past the overhead windows. Downstairs, Walker used a small water container to convince his eyes that gravity was steadily establishing its grasp on the descending orbiter. He found that, at first, he could let go of the container and it would remain weightless.

Discovery sits on the runway at Edwards after her maiden voyage. Photo Credit: NASA

After a while, when he began to sense the onset of gravity, he tried again and saw it drift down to the floor. A third attempt later in the descent would see it fall faster. “I played this little game over the next five minutes or so,” he recalled. “I’d catch it before it hit the ground and put it back up in the air and it seems like after about three or four minutes of that, it was dropping so fast, I couldn’t catch it before it hit the floor and went skittering away somewhere!” The noise outside intensified as they slowed below the speed of sound, although the touchdown at Edwards Air Force Base at 6:38:54 a.m. PDT (9:38:54 a.m. EDT) was perfect and smooth. After two months of delays and a hair-raising pad abort, the shuttle was back in business.

This is part of a series of history articles, which will appear each weekend, barring any major news stories. Next week’s article will focus on the 20th anniversary of STS-64, a multi-faceted shuttle flight in September 1994, which featured the first untethered U.S. EVA in more than a decade.

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